Sensors may be used to detect earthquakes. Some such sensors may also be used in earthquake early warning systems (EEWS) to determine (or estimate) characteristics of earthquakes, such as the epicenter or hypocenter of the earthquake, the magnitude of the surface wave associated with the earthquake and the time of arrival of the surface wave associated with the earthquake. The sensors of prior art earthquake detection systems are generally placed several tens of kilometers or several hundreds of kilometers apart, with the earthquake detection systems comprising data acquisition equipment at each spaced-apart sensor location. This large separation between sensors is typically required in most prior art systems, since most prior art systems have a timing accuracy on the order of seconds or hundreds of milliseconds. The placement of such sensors in close proximity is not possible, where it is desired to know the epicenter of the seismic event, since the epicenter would not be detectable.
Data acquisition equipment (typically located at the same location as the sensors) may be used to log detected data. U.S. Pat. No. 5,381,136 (Powers et al.) describes a remote logger unit for monitoring a variety of operating parameters along a fluid distribution or transmission system. An RF link is activated by which a logger unit alerts a central controller when predetermined operating limits are exceeded. Relatively more distal logger units transmit data to a central controller via relatively more proximate logger units in daisy chain fashion.
U.S. Pat. No. 8,452,540 (Sugawara et al.) describes an earthquake damage spread reducing method and an earthquake damage spread reducing system, for use in a semiconductor manufacturing apparatus, which can predict occurrence of an earthquake and prevent fall down of a boat, thus minimizing damage by the earthquake. An earthquake damage spread reducing system includes a receiving unit for receiving urgent earthquake information, based on preliminary tremors, distributed via a communication network, or alternatively, includes a preliminary tremors detection unit for directly detecting the preliminary tremors. A control unit performs a first step of stopping operation of a semiconductor manufacturing apparatus, based on the urgent earthquake information received or on the preliminary tremors detected, as well as performs a second step of holding a boat to prevent fall of the boat, in which objects to be processed are loaded in a multistage fashion.
US Patent Application No. 2014/0187142 (Liu et al.) describes a seismic alarm system designed to alarm users of an upcoming seismic event and other natural disasters, and aid victims' survival after an earthquake. The seismic alarm system includes an accelerometer, a controller, an acoustic-to-electric transducer for acoustic pattern detection, and RF module to receive emergency radio signals. The alarm system has central controlling unit that sets off an alarm after processing signals from several modules and components. The accelerometer detects seismic P wave acceleration changes for early earthquake detection. The acoustic-to-electric transducer detects human acoustics or predetermined acoustic patterns, then initiates an alarm that brings rescue attention to survivors. The RF module is tuned to receive emergency radio signals.
U.S. Pat. No. 5,910,763 (Flanagan et al.) describes a system that provides an area warning to a specific general population of an earthquake prior to the arrival of the hazardous ground motion typically associated with earthquakes, and of approaching natural disasters that could impact an area. This area advanced warning thereby provides time for users to seek shelter and through automated means to reduce property damage as well as injuries and lives lost. A preferred embodiment utilizes a plurality of “Local Station Detector Sites”, equipped with earthquake seismic motion detectors and microprocessors designed to provide a profile of existing ground motion to a “Central Processing Site” in conjunction with further analysis of similar signals from multiple sites. A warning instruction is then transmitted back to all appropriate Local Station Detector Sites to initiate transmission of local area warnings to a general population of all users in an appropriate and specific geographic area with minimal possibility of false alarms. Additionally all Local Station Detector Sites are equipped to receive notification transmissions from the Central Processing Site, which have been initiated by “Public Safety Offices” for other natural disasters, and transmit appropriate warning signals to the general population of users in specific geographic areas.
US Patent Application No. US2015/0195693 (Hoorianin et al.) describes a mobile phone and tablet-based earthquake early warning system that utilizes the on board accelerometer, gyroscope, GPS and other location and movement sensing technologies built into today's mobile smart phones and tablet devices to detect an earthquake event and send an alarm to those in nearby locations that could be adversely affected by the event.
Existing EEWS systems use various data acquisition techniques to obtain seismic activity measurements. Seismic activity measurements reveal risks of potential damage from earthquakes and provide early warning of the arrival of the S-wave (secondary wave) associated with an earthquake, making such measurements useful for preventing and/or minimizing human injury/death and damage to property. When an earthquake occurs, casualties and damage are typically positively correlated with preparedness and amount of warning time.
The US Geological Survey states that early warning of earthquakes “can give enough time to slow and stop trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.”
The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion. The Seismological Society of America states that “Earthquake Early Warning Systems (EEWS) could also reduce the number of injuries in earthquakes by more than 50%.”
Many countries, including the US, Canada and Japan, are investing in the deployment of EEWS, as are government authorities at other levels.
The Seismological Society of America states that EEWS, “like warnings for other natural disasters, such as tornadoes, hurricanes, and tsunamis, is a forecast of activity that is imminent. However, unlike hurricane warnings, which can come days in advance of severe weather, or tsunami warnings, which build over the course of a few minutes to a few hours before the tsunami makes landfall, earthquakes have a much shorter lead time, shorter even than a funnel cloud that starts spiraling toward the earth. A warning could be just seconds. This short warning time is a product of the physical process of an earthquake rupture. EEWS typically use seismometers to detect the first signature of an earthquake (P-wave), to process the waveform information, and to forecast the intensity of shaking that will arrive after the S-wave. For local EEWS installations, the P-wave is detected onsite (i.e., at the user location), and the difference between the P- and S-wave arrival times defines the maximum alert time. For regional networks, the P-waves are detected by sensors closest to the epicenter, and estimates are immediately relayed to earthquake alerting applications (TV, smart phones, radio, etc.) to provide businesses, citizens, and emergency responders more advance knowledge of the expected arrival and intensity of shaking at their location.”
Prior art EEWS systems make use of electronic sensors measure physical quantities (such as velocity, acceleration strain, temperature, crack, pressure, etc.) and convert these physical quantities into signals using suitable reading instruments (e.g. transducers). The particular reading instrument varies depending on the type of sensor. For example, geophones typically incorporate a wire coil with a magnet in the middle that is free to move. As the sensor shakes or vibrates (as is the case during an earthquake), the magnet moves through the coil producing a current, which can be measured to record the variations. To determine the epicenter and the magnitude of an earthquake in accordance with prior art EEWS systems, three to four sensor locations (typically spaced apart by tens of kilometers or hundreds of kilometers) detect the earthquake and communicate with each other to exchange data. The accuracy of epicenter and magnitude predictions depends on the time synchronization between sensor locations and network communication speed between sensor locations.
While existing EEWS systems provide some early warning and damage reduction capabilities, they have at least the following deficiencies:                To accurately detect the epicenter and magnitude of the earthquake, the sensors must typically be located relatively far apart (typically 10's or 100's of km) from one another, since the timing accuracy of the systems is on the order of seconds or hundreds of milliseconds. Data from all sensors of interest must typically be gathered and correlated, and the data must then be processed before determining if a warning is to be issued. When sensor locations are hundreds of kilometers apart, gathering, correlating and processing data are time consuming, thereby reducing potential warning time. Some EEWS systems, for example, the system described in U.S. Pat. No. 9,372,272 (Price et al.) comprise sensors that can be placed less than 500 m apart from each other; however, such sensors must be hard wired to a central controller. This is undesirable. First, installation is difficult and complicated since long cables must be installed, which may require digging channels in the earth or through concrete. Second, the long length of the cables could lead to signal degradation and unwanted noise, resulting in unreliable detection of the P-wave signal.        Existing EEWS system employ centralized processing of data, which typically involves transmittal of large amounts of data, resulting in a corresponding need for high bandwidth, highly reliable and costly network infrastructure.        Existing EEWS systems also have a need to transfer high volumes of data via network communications. These data transfer requirements dictate a corresponding need for high bandwidth network capability. Establishing and/or maintaining high bandwidth networks over large areas and/or remote locations can be very difficult and costly.        Generating a warning with time to arrival of the damaging S-wave requires sensors at multiple locations with time synchronization between locations and high quality network communication between locations. The network communication must be able to transmit signals between the various components of the system with minimal latency in order to be an effective EEWS. There is thus a high need for low latency network communications which may not be readily available at all times.        When sensors are far apart, the geology from the epicenter to each sensor can differ significantly. Such geological differences may result in inaccurate prediction of the time and magnitude of the oncoming S-wave. Alternatively, such geological differences require the use of accurate geological models which are costly and time consuming to generate.        When existing EEWS systems issue warnings, these warnings are blanket warnings to all within the warning area. It is up to the individuals or organizations within the warning area to interpret the warning, assess the danger and take any desired actions. Some choose to do nothing simply because they do not know what to do or do not think they are in danger. Prior art EEWS systems have no knowledge an individual's or organization's situation or location or least do not incorporate any such knowledge into any applicable recommended courses of action. For instance, if an individual is driving on the freeway, the recommendation should be to pull over safely and stop. However, if the individual is driving in a tunnel, pulling over and stopping inside the tunnel is not the correct action. The preferred action would be to drive through the tunnel and then pull over and stop. As another example, because the generic warnings issued by prior art EEWS systems lack situational awareness within the warning area, such generic warnings can result in an organization unnecessarily shutting down equipment or processes, which can cause unnecessary losses and create more harm than good. Still further, generic warnings (without situational awareness) issued by prior art EEWS systems can cause unnecessary panic.        In many existing EEWS systems, the decision-making and actions are left for individual manual execution, which is unreliable and inefficient. In many cases, manual execution is not possible due to the short time available prior to arrival of the damage-causing S-wave. Manual execution is prone to errors. Shutdown of critical equipment typically requires concentration and thought, which may be lacking in panic-driven conditions.        Some existing EEWS systems do incorporate autonomous decision-making, but these EEWS systems have been historically unreliable, are expensive or non-viable, and/or have a false-positive ratio which is too high. In addition, these autonomous EEWS systems must typically be placed over a wide area with complicated networking schemes that make them impractical for use by smaller scale businesses and individuals. These autonomous EEWS systems are typically limited to large-scale deployment by government institutions or the like. Some existing autonomous EEWS systems have not operated reliably when earthquakes actually occur. These systems may work well in the laboratory under simulated or mechanically generated vibration conditions, but can tend to fail during actual earthquakes. Also, earthquakes do not occur regularly, making it difficult to perform thorough field testing.        Existing EEWS systems only allow for one-way communication from the EEWS system to individuals (affected individuals and emergency response teams) in the warning zone over communication channels which typically require high priority and reliability. Emergency response teams typically use their own communication methods which are only accessible to the public through single points of entry, such as dedicated (call-in) phone numbers. The mere volume of calls during a disaster makes these call-in numbers congested resulting in long wait times. Other than such call-in numbers, there is no provision in existing EEWS systems for affected individuals to communicate back to emergency response teams, family and friends. As a result, affected individuals and emergency response teams may be tend to rely on other available communication services, such as social media, to communicate their condition, location and emergency needs. This individual use of distributed communication channels such as social media is highly inefficient and unreliable, especially when data networks become congested in the affected area (as is typical). Also, not all people affected are connected via social media and not all emergency response teams monitor social media. Further, general data communications over communication networks during a disaster can get highly congested due to the high volume of messages and messages typically do not receive high priority.        Some existing EEWS systems, such as the one depicted in US Patent Application No. 2015/0195693 (Hooriani et al.), use sensors in mobile phones and tablets to detect earthquakes and provide warnings. However, such sensors cannot detect the P-wave and can only detect large movements of the S-wave, so they cannot provide a warning of a pending S-wave.        Existing EEWS systems do not monitor the surrounding structures and equipment, so any damage resulting from a seismic event cannot be qualified and quantified. Existing EEWS systems report on the seismic event parameters only and have no knowledges of parameters (other than those of the seismic event) in the region in which the warning is issued. It is up to the use of the existing EEWS system to determine the safety risks and/or potential damage that is likely to result from a seismic event. It would be useful to know if the damage from a seismic event results in (or would be likely to result in) safety risks to the personnel using the equipment or utilizing the structure. Alarms and warning can then be issued as necessary to prevent further injuries or damage.        
Accordingly, there is a general desire for systems and methods for early warning of seismic events that make use of autonomous actions, which autonomous actions may be executed quickly and efficiently, without the need for manual intervention. There is a general desire for such systems and methods to overcome or at least ameliorate some the drawbacks with prior art EEWS systems.
There is also a general desire for systems and methods for early warning of seismic events which incorporate situational awareness into any warnings that are issued in the event of a seismic event.
There is also a general desire for systems and methods for early warning of seismic events which can monitor and/or control communications (e.g. multi-way communications) through a suitable communication network.
There is also a general desire for systems and methods for early warning of seismic events which provide and maintain reliable, secure and rapid communications.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.